The present invention relates to granulocyte colony-stimulating factor-containing formulations, and particularly granulocyte colony-stimulating factor-containing formulations stabilized by preventing loss and inactivation of active Ingredients due to adsorption to container walls, aggregation, polymerization, oxidation or the like.
Granulocyte colony-stimulating factor (hereinafter also referred to as xe2x80x9cG-CSFxe2x80x9d) is a glycoprotein having a molecular weight of about 20,000 and acting on precursor cells of neurophils to promote their proliferation and differentiation to maturation.
Since we purified high-purity human G-CSF by culturing a cell line collected from tumor cells of a patient with cancer of the floor of the mouth, the human G-CSF gene was successfully cloned and, at present, recombinant human G-CSF can be produced in mass in animal cells by genetic engineering. We also succeeded in converting this purified G-CSF into a formulated product, which Is supplied to the market as an antiinfective agent (Japanese Patent No. 2116515).
G-CSF is used in a very small amount, i.e. a formulation containing 0.1-1000 xcexcg (preferably 5-500 xcexcg) of G-CSF is normally administered once to seven times per week per adult. However, this G-CSF is adsorptive to walls of ampoules, syringes or the like. G-CSF is also unstable and susceptible to extrinsic factors such as temperature, humidity, oxygen, UV rays or the like to undergo physical or chemical changes including aggregation polymerization or oxidation, resulting in great loss of activity.
Thus, various formulation designs have been made to supply stable G-CSF formulations to the market. For example, formulations containing a buffer selected from acetic acid, lactic acid, citric acid, maleic acid, phosphoric acid and salts thereof or arginine and salts thereof were proposed (JPA No. 505610/96). G-CSF formulations containing 1-10,000 parts by weight of a surfactant as a stabilizer per part by weight of G-CSF were also proposed (JPA No. 146826/88). The latter publication describes that the level of the surfactant, particularly its lower limit is critical to prevent loss of G-CSF and to achieve stabilization in G-CSF-containing liquid formulations.
An object of the present invention is to provide a G-CSF formulation, which enables a reduction in the complexity of the production process and which is more stable for extended storage.
As a result of careful studies to achieve the above object, we accomplished the present invention on the basis of the finding that a stable G-CSF liquid formulation can be obtained even when it contains a very small amount of a surfactant as a stabilizer.
Accordingly, the present invention provides a stable granulocyte colony-stimulating factor-containing formulation comprising a granulocyte colony-stimulating factor and 0.0001-1 parts by weight of at least one pharmaceutically acceptable surfactant per part by weight of the granulocyte colony-stimulating factor and having a pH of 7 or less.
As used herein, stabilization means that the percentage of remaining G-CSF is kept at 95% or more after storage at 25xc2x0 C. for 6 months or 75% or more after storage at 40xc2x0 C. for 2 weeks.